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Under the EU Clean Sky 2 research project InSPIRe – Innovative Systems to Prevent Ice on Regional Aircraft, numerical and experimental studies have been performed to investigate the potential to minimise the electrical power required for wing ice protection on a regional aircraft wing. In a standard electrothermal de-ice protection scheme there is a parting strip heater which runs along the full spanwise protected extent and is permanently powered. This splits the ice formation on the leading edge into an upper and lower region, which makes it easier to shed. However, the parting strip is relatively energy intensive and contributes a significant portion of the overall power demand. Developing a system which is able to provide the desired ice protection function without a parting strip would therefore offer a substantial power saving. The great difficulty with such a system is in ensuring that acceptable ice shedding occurs.

Ice adhesion characterization relies heavily on experimental data, especially when dealing with fracture parameters. In this paper, a complementary framework encompassing experimental testing with the numerical treatment of the fracture variables is proposed to provide a physical description of adhesive fracture propagation at the interface of an iced structure. The tests are based on a quasi-static flexural testing setup composed of a displacement-driven actuator and an iced plate. The measured crack length and plate deflection provide the data to be analyzed by the Virtual Crack Closure Technique in order to approximate the critical energy release rate required to study adhesive fracture propagation. The critical energy release rate in mode II is under-predicted and its value is approximated using its counterpart in mode I.

The European Union’s Horizon 2020 programme has funded the SENS4ICE (Sensors for Certifiable Hybrid Architectures for Safer Aviation in Icing Environment) international collaboration flagship programme. Under this programme a number of different organizations have developed ice detection technologies, specifically aimed at providing information to differentiate between ‘classical’ Appendix C icing conditions and the larger droplets found in Appendix O icing. As a partner within the SENS4ICE project, AeroTex UK has developed an ice detection concept called the Atmospheric Icing Patch (AIP). The sensor utilizes a network of iso-thermal sensors to detect icing and differentiate between small and large droplet icing conditions. This paper discusses the development of the sensor technology with a focus on the outcomes of the flight testing performed on the Embraer Phenom 300 platform during early 2023.

Aircraft icing is a significant issue for aviation safety. In this paper, recent developments for calculating the trajectory of non-spherical particles are used to determine the trajectory and impingement of ice crystals in aircraft icing scenarios. Two models are used, each formulated from direct numerical simulations, to give the drag, lift and torque correlations for various shaped particles. Previously, within the range of Reynolds number permitted in this study, it was only possible to model the trajectory and full rotational progression of cylindrical particles. The work presented in this paper allows for analysis of a wider range of ice shapes that are commonly seen in icing conditions, capturing the dynamics and behaviours specific to ice crystals. Previous limitations relate to the in ability to account for particle rotation and the dependency of force correlations on the measure of particle sphericity - which are now overcome.

This paper details the motivation, development and validation of a rapid 3D Lagrangian impingement code, Trajectory and Catch 3D+ (TAC3D+). AeroTex’s motivation to develop a 3D Lagrangian method was primarily driven by the inherent mesh dependent dissipation effect found in their 3D Eulerian Water Catch code (EWC) [1]. Studies performed by AeroTex have shown that for geometries where there are aft impingement regions that are partly shadowed by a more forward impingement region, the level of water flux dissipation can be significant, particularly if the mesh is coarse and the impingement region is far aft. Examples of issues where this may be a particular issue would be impingement on a centerline aft mounted engine or the calculation of impingement on the wing root/belly fairing. The code has been developed around a modified version of the OpenFOAM Lagrangian solver.

This paper details the process involved in the numerical optimisation of a helicopter engine inlet electrothermal ice protection system. Although the process was developed using a production aircraft, it is demonstrated here using a generic intake and flight conditions, due to confidentiality of the actual design. The process includes adherence to the overall system design objectives (maximum power demand), including tolerances required to account for an industrial system (aircraft voltage variation, manufacturing tolerances). The numerical optimisation was performed using a combination of 2D and 3D methods to define the required heated area, power density, locations and settings for temperature control sensors. The use of 2D design tools allows a rapid iteration process to be performed, leading to the possibility of a higher level of optimisation within the allowable time-frame compared to the use of full 3D methods.

The introduction of ice-phobic coatings promises to allow passive ice protection systems to be developed particularly for rotating systems such as propellers. The centrifugal force field combined with reduced adhesive strength can produce a self-shed capability limiting the amount of ice build-up. The size and shed time of ice shed from a propeller is predicted using a process that determines ice shape, ice growth rate and both internal and ice-structure interface stresses. A simple failure model is used to predict the onset of local failure and to propagate damage in the ice until local ice shedding is obtained. Recommendations are made on developing the model further.